At approximately 1000 hours on 26 August, Unit 1 experienced 

 problems forcing a reactor shutdown and a partial shutdown of 

 the circulating system. The total circulating system was 

 operating at 94% capacity at 1200 hours resulting in a 6% 

 reduction in the volume of water discharged at the quarry cut 

 during the high slack tide mapping session. Discharge volume 

 hdQ dropped to 89% of capacity by the beginning of the 

 maximum ebb tide mapping session at 1430. Considering the 

 nearly ideal survey conditions, these reductions in discharge 

 should not greatly alter the patterns and magnitudes of the 

 thermal plume as they are presented. Adverse wind and sea 

 conditions could be expected to have a much greater impact on 

 the thermal plume. 



4.4 



Re circulation Data 



Dye concentration monitoring =", t the Unit 1 discharge was 

 begun at 1300 on 23 August to determine whether discharge 

 water was recirculating back through the system. Only 

 background levels were recorded for the first 26 hours 

 (Figure 9) after which dye concentrations rose to 

 approximately 0.12 ppb where they remained for the remainder 

 of the survey. Dye concentrations at the quarry cut reached 

 a relatively stable level 3 hours after dye injection began 

 at 1500 on 23 August-so that it took between 21 and 24 hours 

 for dye to be sensed at the Unit 1 discharge. Dye 

 concentrations recorded at Unit 1 equate to a temperature 

 increase of less than 1°F in the waters being recirculated 

 through Unit 1. This may be an over-estimation of the actual 

 level of thermal recirculation since radiant cooling of the 

 water during the 21-24 hour transit time would reduce the 

 temperature of the water without reducing the dye 

 concentration. Mechanisms for temperature exchange should be 

 considered with recirculation times of this length. 



17 - 



